Liner for a Gas Turbine Engine Combustor

ABSTRACT

A gas turbine engine combustor includes a liner defining at least in part a combustion chamber, a first side exposed to the combustion chamber, a second side opposite the first side, and a film cooling hole extending from the second side to the first side, the film cooling hole defining an outlet on the first side of the liner, the liner including an airflow feature on the first side of the of the liner adjacent to the outlet of the film cooling hole to increase a cooling of the liner.

FIELD

The present subject matter relates generally to a liner for a gas turbine engine combustor.

BACKGROUND

A gas turbine engine typically includes an inlet, one or more compressors, a combustor, and at least one turbine. The compressors compress air which is channeled to the combustor where it is mixed with fuel. The mixture is then ignited for generating hot combustion gases. The combustion gases are channeled to the turbine(s) which extracts energy from the combustion gases for powering the compressor(s), as well as for producing useful work to propel an aircraft in flight or to power a load, such as an electrical generator. For example, in at least certain embodiments, the gas turbine engine may further include a fan driven by the one or more turbines.

Additionally, typical combustion sections include one or more liners defining a combustion chamber. Film cooling holes may be defined within these liners to form a cooling air film on a hot side of the liner to maintain the liner within a desired operating temperature range. Accordingly, the film cooling holes allow for a stream of relatively cool compressed air to flow into the combustion chamber. Notably, however, hotspots may form around the stream of compressed air flowing through the film cooling holes into the combustion chamber, potentially damaging or prematurely wearing the liner. Accordingly, a liner capable of reducing, or better managing, these hotspots would be useful.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one exemplary embodiment of the present disclosure, a gas turbine engine combustor is provided. The gas turbine engine combustor includes a liner defining at least in part a combustion chamber, a first side exposed to the combustion chamber, a second side opposite the first side, and a film cooling hole extending from the second side to the first side, the film cooling hole defining an outlet on the first side of the liner, the liner including an airflow feature on the first side of the of the liner adjacent to the outlet of the film cooling hole to increase a cooling of the liner.

In certain exemplary embodiments the combustion chamber defines an airflow direction over the outlet of the film cooling hole on the first side of the liner, and wherein the airflow feature is positioned at least partially downstream of the outlet along the airflow direction.

For example, in certain exemplary embodiments the airflow feature is a first airflow feature, wherein the liner further includes a second airflow feature also positioned at least partially downstream of the outlet along the airflow direction, wherein the combustion chamber further defines a transverse direction perpendicular to the airflow direction, and wherein the second airflow feature is spaced from the first airflow feature along the transverse direction.

For example, in certain exemplary embodiments the first airflow feature is a protrusion on the first side of the liner extending into the combustion chamber, and wherein the second airflow feature is an indentation on the first side of liner.

In certain exemplary embodiments the combustion chamber defines an airflow direction over the outlet of the film cooling hole on the first side of the liner, and wherein the airflow feature is positioned at least partially upstream of the outlet along the airflow direction.

For example, in certain exemplary embodiments the airflow feature is a first airflow feature, wherein the liner further includes a second airflow feature also positioned at least partially upstream of the outlet along the airflow direction, wherein the combustion chamber further defines a transverse direction perpendicular to the airflow direction, and wherein the second airflow feature is spaced from the first airflow feature along the transverse direction.

For example, in certain exemplary embodiments the first airflow feature is a protrusion on the first side of the liner extending into the combustion chamber, and wherein the second airflow feature is an indentation on the first side of liner.

For example, in certain exemplary embodiments the first airflow feature is a protrusion on the first side of the liner extending into the combustion chamber, and wherein the second airflow feature is also a protrusion on the first side of the liner extending into the combustion chamber.

For example, in certain exemplary embodiments the liner further includes a third airflow feature and a fourth airflow feature, wherein the third airflow feature and the fourth airflow feature are each positioned at least partially downstream of the outlet along the airflow direction and spaced from one another along the transverse direction.

For example, in certain exemplary embodiments at least one of the first airflow feature, the second airflow feature, the third airflow feature, and the fourth airflow feature is a protrusion extending into the combustion chamber, and wherein at least one of the first airflow feature, the second airflow feature, the third airflow feature, and the fourth airflow feature is an indentation on the first side of liner.

In certain exemplary embodiments the combustion chamber defines an airflow direction over the outlet of the film cooling hole on the first side of the liner, wherein the airflow feature is a first airflow feature, wherein the liner further includes a second airflow feature, wherein the first and second airflow features are aligned with one another and the outlet of the film cooling hole along the airflow direction, and wherein the first airflow feature is positioned adjacent to the second airflow feature along the airflow direction.

In certain exemplary embodiments the combustion chamber defines an airflow direction over the film cooling hole on the first side of the liner and a transverse direction perpendicular to the airflow direction, wherein the airflow feature defines a length along the airflow direction and a width along the transverse direction, and wherein the width of the airflow feature is greater than the length of the airflow feature and up to about five times the length of the airflow feature.

In certain exemplary embodiments the film cooling hole defines a diameter at the outlet, wherein the airflow feature defines a width and a height, wherein the width of the airflow feature is greater than or equal to about 0.1 times the diameter of the of the film cooling hole and up to about 6 times the diameter of the film cooling hole, and wherein the height of the airflow feature is greater than or equal to about 0.1 times the diameter of the film cooling hole and up to about 6 times the diameter of the film cooling hole.

In certain exemplary embodiments the film cooling hole is a first film cooling hole of a plurality of film cooling holes defined by the liner.

In certain exemplary embodiments the film cooling hole defines a substantially constant diameter along a length thereof.

In another exemplary embodiment of the present disclosure, a gas turbine engine is provided. The gas turbine engine includes a combustion section including a combustor liner, the combustor liner defining at least in part a combustion chamber, a hot side exposed to the combustion chamber, a cold side opposite the hot side, and a plurality of film cooling holes extending from the cold side to the hot side, the plurality of film cooling holes each defining an outlet on the hot side of the liner, the liner including a plurality of airflow features on the hot side of the of the liner, each airflow feature of the plurality of airflow features positioned adjacent to the outlet of one of the plurality of film cooling holes to increase a cooling of the liner.

In certain exemplary embodiments the combustion chamber defines an airflow direction over the outlets of the plurality of film cooling holes on the hot side of the liner, and wherein the airflow features are each positioned at least partially downstream of the outlet of one of the plurality of film cooling holes along the airflow direction.

In certain exemplary embodiments the combustion chamber defines an airflow direction over the outlets of the plurality of film cooling holes on the hot side of the liner, and wherein the airflow features are each positioned at least partially upstream of the outlet of one of the plurality of film cooling holes along the airflow direction.

In certain exemplary embodiments the combustion chamber defines an airflow direction over the outlets of the plurality of film cooling holes on the hot side of the liner and a transverse direction perpendicular to the airflow direction, wherein each airflow feature defines a length along the airflow direction and a width along the transverse direction, and wherein the width of each airflow feature is greater than the length of the airflow feature and up to about five times the length of the airflow feature.

In certain exemplary embodiments a first film cooling hole of the plurality of film cooling holes defines a diameter at its outlet, wherein a first airflow feature of the plurality of airflow features defines a width and a height, wherein the width of the first airflow feature is greater than or equal to about 0.1 times the diameter of the of the first film cooling hole and up to about 6 times the diameter of the first film cooling hole, and wherein the height of the first airflow feature is greater than or equal to about 0.1 times the diameter of the first film cooling hole and up to about 6 times the diameter of the first film cooling hole.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended Figs., in which:

FIG. 1 is a perspective view of a gas turbine engine combustor in accordance with an exemplary embodiment of the present disclosure.

FIG. 2 is a perspective view of a section of a liner of the exemplary gas turbine engine combustor of FIG. 1.

FIG. 3 is a plan view of one side of a section the exemplary liner FIG. 2.

FIG. 4 is a cross-sectional view of the exemplary liner of FIG. 2 along an airflow direction.

FIG. 5 is a cross-sectional view of a liner in accordance with another exemplary embodiment of the present disclosure along an airflow direction.

FIG. 6 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with another exemplary embodiment of the present disclosure.

FIG. 7 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with yet another exemplary embodiment of the present disclosure.

FIG. 8 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with another exemplary embodiment of the present disclosure.

FIG. 9 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with yet another exemplary embodiment of the present disclosure

FIG. 10 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with still another exemplary embodiment of the present disclosure.

FIG. 11 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with another exemplary embodiment of the present disclosure.

FIG. 12 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with yet another exemplary embodiment of the present disclosure

FIG. 13 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with still another exemplary embodiment of the present disclosure.

FIG. 14 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with yet another exemplary embodiment of the present disclosure.

FIG. 15 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with still another exemplary embodiment of the present disclosure.

FIG. 16 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with yet another exemplary embodiment of the present disclosure.

FIG. 17 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with still another exemplary embodiment of the present disclosure.

FIG. 18 is a plan view of one side of a section of a liner of a gas turbine engine combustor in accordance with yet another exemplary embodiment of the present disclosure.

FIG. 19 is a cross-sectional view of the exemplary liner of FIG. 18 along a tangential direction.

It will be appreciated that use of the same or similar numbers throughout the Figures may refer to same or similar part.

DETAILED DESCRIPTION

Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention.

As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

The terms “forward” and “aft” refer to relative positions within a gas turbine engine or vehicle, and refer to the normal operational attitude of the gas turbine engine or vehicle. For example, with regard to a gas turbine engine, forward refers to a position closer to an engine inlet and aft refers to a position closer to an engine nozzle or exhaust.

The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.

The terms “coupled,” “fixed,” “attached to,” and the like refer to both direct coupling, fixing, or attaching, as well as indirect coupling, fixing, or attaching through one or more intermediate components or features, unless otherwise specified herein.

The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.

Approximating language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or machines for constructing or manufacturing the components and/or systems. For example, the approximating language may refer to being within a 10 percent margin.

Here and throughout the specification and claims, range limitations are combined and interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views, FIG. 1 shows a combustor 10 of the type suitable for use in a gas turbine engine. For example, the exemplary combustor 10 depicted may be utilized within an aeronautical gas turbine engine, such as a turboshaft engine, turboprop engine, turbojet engine, etc. Additionally, or alternatively, the combustor 10 may be utilized in any other suitable gas turbine engine, such as an aeroderivative gas turbine engine, a power generation gas turbine engine, etc. As shown, combustor 10, or rather the gas turbine engine within which the combustor 10 is installed (not shown) defines a longitudinal direction L, a radial direction R, and a circumferential direction C.

As shown, the combustor 10 includes a liner, and more specifically, an outer liner 12 and an inner liner 14 disposed between an outer combustor casing 16 and an inner combustor casing 18. Outer and inner liners 12, 14 are radially spaced from each other to define at least in part a combustion chamber 20. Outer liner 12 and outer casing 16 form an outer passage 22 therebetween, and inner liner 14 and inner casing 18 form an inner passage 24 therebetween. A cowl assembly 26 is mounted to the upstream ends of outer and inner liners 12, 14. An annular opening 28 is formed in cowl assembly 26 for the introduction of compressed air into combustor 10. The compressed air is supplied from a compressor (not shown) in a direction generally indicated by arrow 27 of FIG. 1. The compressed air passes principally through annular opening 28 to support combustion and partially into outer and inner passages 22 and 24 where it is used to cool the liners 12, 14.

Disposed between and interconnecting the outer and inner liners 12, 14 near their upstream ends is an annular dome plate 30. A plurality of circumferentially spaced swirler assemblies 32 is mounted in dome plate 30. Each swirler assembly 32 receives compressed air from annular opening 28 and fuel from a corresponding fuel tube 34. The fuel and air are swirled and mixed by swirler assemblies 32, and the resulting fuel/air mixture is discharged into combustion chamber 20. It is noted that although FIG. 1 illustrates one preferred embodiment of a single annular combustor, the present invention is equally applicable to any type of combustor, including double annular combustors, which uses multi-hole film cooling.

It will be appreciated, however, that in other exemplary embodiments, the combustor 10 may have any other suitable configuration. For example, in other exemplary embodiments, the combustor 10 may be configured as one of a pulse detonation combustor, a rotating detonation combustor, a can combustor, a cannular combustor, or any other suitable type of combustor.

Outer and inner liners 12, 14 each have an annular and axially extending configuration. In at least certain embodiments, the outer and inner liners 12, 14 may be a single shell, such as a single metal or metal alloy shell. However, in other embodiments, the outer and inner liners 12, 14 may instead be formed of a ceramic matrix composite material, or any other suitable material. Further, it will be appreciated that the outer and inner liners 12, 14 may be formed through any suitable process. For example, in certain embodiments, one or both of the outer and inner liners 12, 14 may be formed using an additive manufacturing, or 3D printing, process. Such may provide for a relatively cost-effective means for forming a liner having the various airflow features described below.

Referring still to FIG. 1, the outer liner 12 defines a first side and a second side opposite the first side. For the embodiment depicted, the first side is a hot side 36 exposed to the combustion chamber 20 and facing the hot combustion gases in combustion chamber 20, and the second side is a cold side 38 in contact with the relatively cool air in outer passage 22. Similarly, inner liner 14 defines a first side and a second side opposite the first side. As with the outer liner 12, the first side of the inner liner 14 is a hot side 40 exposed to the combustion chamber 20 and facing the hot combustion gases in combustion chamber 20, and the second side is a cold side 42 in contact with the relatively cool air in inner passage 24. Both liners 12 and 14 include a large number of closely spaced film cooling holes 44 formed therein.

Moreover, as is also depicted in FIG. 1, and as will be described in more detail below, the outer liner and inner liner 12, 14 each define a plurality of film cooling holes 44 therein to form a cooling film on the first sides/hot sides 36, 40 thereof. Additionally, the outer liner and inner liner 12, 14 each also define a plurality of dilution holes 48 for introducing dilution air to the combustion chamber 20. The dilution holes 48 are arranged in rows, with the rows spaced generally along an axial direction A of the gas turbine engine, and the dilution holes 48 of each row spaced generally along a circumferential direction C of the gas turbine engine. Additionally, as shown, the dilution holes 48 are disposed in each of outer and inner liners 12, 14. Dilution holes 48 are generally smaller in number than the film cooling holes 44, and each dilution hole 48 has a cross-sectional area that is substantially greater than the cross-sectional area of one of the film cooling holes 44. Dilution holes 48, and to a smaller extent the film cooling holes 44, serve to admit dilution air into combustor chamber 20 that will dilute the combustion products to get a leaner air/fuel mixture, quickly and efficiently.

For example, conventionally the film cooling holes 44 in typical combustor liners have relatively small diameters on the scale of between about 0.01 inches and about 0.1 inches, with a circumferential hole spacing between about 0.05 inches and about 0.25 inches. By contrast, the dilution holes 48 conventionally have a relatively large diameters, such as greater than about 0.15 inches and up to about 1.5 inches.

Referring now to FIG. 2, a perspective, cut out view of a liner 50 for a combustor of a gas turbine engine in accordance with an exemplary embodiment of the present disclosure is provided. In certain exemplary embodiments, the liner 50 of FIG. 2 may be incorporated into the exemplary combustor 10 described above with reference to FIG. 1. For example, in certain exemplary embodiments, the liner 50 of FIG. 2 may be one of the inner liner 14 or outer liner 12 of the combustor 10 of FIG. 1.

Accordingly, it will be appreciated that liner 50 defines at least in part a combustion chamber 20, a first side 36, a second side 38 opposite the first side 36, and a film cooling hole 44 extending between the first side 36 and second side 38. For the embodiment depicted, the first side 36 is a hot side, and accordingly, the first side 36 is exposed to (and at least partially defines) the combustion chamber 20 (see also FIG. 1). Additionally, in such a manner it will be appreciated that the film cooling hole 44 extends from the second side 38 to the first side 36, defining an outlet 52 on the first side 36. Furthermore, during operation of the combustor, the combustion chamber 20 defines an airflow direction A over the dilution hole on the first side 36 of the liner 50, as well as a transverse direction T perpendicular to the airflow direction A. The transverse direction T is also parallel to a surface 54 of the liner 50 on the first side 36, and may be locally aligned with a circumferential direction of the gas turbine engine including the combustor (e.g., circumferential direction C described above with respect to FIG. 1).

More specifically, as with the embodiment depicted in FIG. 1, the film cooling hole 44 is a first film cooling hole 44A of a plurality of film cooling holes 44 defined by the liner 50. Each of the plurality of film cooling holes 44 are spaced a distance S from one another along the transverse direction T and a distance P from one another along the airflow direction A. Notably, however, in other exemplary embodiments, the plurality of film cooling holes 44 may be arranged in any other suitable manner.

Referring now also to FIG. 3, a plan view of the first side 36 (i.e., the hot side) of the exemplary liner 50 of FIG. 2 is provided. As is depicted schematically, the liner 50 further includes an airflow feature 56 on the first side 36 of the liner 50 adjacent to the outlet 52 of the film cooling hole 44 to increase a cooling of the liner 50, and more specifically, adjacent to a first outlet 52A of the first film cooling hole 44A to increase a cooling of the liner 50. As used herein, the term “adjacent to the outlet of the film cooling hole,” with reference to a positioning of an airflow feature, refers to such airflow feature being spaced (edge-to-edge) from the outlet of the respective film cooling hole a distance no more than twice the diameter of the film cooling hole.

More specifically, still, as noted above, the combustion chamber 20 defines the airflow direction A over the outlet 52 of the film cooling hole 44 on the first side 36 of the liner 50, and further defines the transverse direction T perpendicular to the airflow direction A. For the embodiment shown, the airflow feature 56 is positioned at least partially upstream of the outlet 52A of the first film cooling hole 44A along the airflow direction A. Moreover, for the embodiment shown, the airflow feature 56 is a first airflow feature 56A and the liner 50 further includes a second airflow feature 56B also positioned at least partially upstream of the outlet 52A of the first film cooling hole 44A along the airflow direction A. Further, for the embodiment shown, the second airflow feature 56B is spaced from the first airflow feature 56A along the transverse direction T.

Referring now also to FIG. 4, providing a cross-sectional view of the liner 50 depicted in FIG. 3, along Line 4-4 in FIG. 3, it will be appreciated that for the embodiment shown, the first airflow feature 56A is a protrusion on the first side 36 of the liner 50 extending into the combustion chamber 20, and further that the second airflow feature 56B is also a protrusion on the first side 36 of the liner 50 also extending into the combustion chamber 20. For the embodiment shown, it will be appreciated that the first airflow feature 56A defines a height 58, a width 60, and a length 62 (see FIG. 3). The height 58 is defined in a direction perpendicular to the airflow direction A and transverse direction T relative to the surrounding surface 54 of the first side 36 of the liner 50. The width 60 is defined along the transverse direction T. The length 62 is defined along the airflow direction A. For the embodiment shown, it will further be appreciated that the first film cooling hole 44A defines a diameter 64 (FIG. 3) at the outlet 52. The width 60 of the airflow feature 56 is greater than or equal to about 0.1 times the diameter 64 and up to about six (6) times the diameter 64, the height 58 of the airflow feature 56 is greater than or equal to about 0.1 times the diameter 64 and up to about six (6) times the diameter 64, and the length 62 of the airflow feature 56 is also greater than or equal to about 0.1 times the diameter 64 and up to about six (6) times the diameter 64. For example, one or more of the width 60, height 58, and/or length 62 may be greater than or equal to about 0.25 times the diameter 64, such as greater than about 0.5 times the diameter 64, such as greater than or equal to the diameter 64, such as less than or equal to about five (5) times the diameter 64, such as less than or equal to about four (4) times the diameter 64. Notably, the second airflow feature 56B may also define a height 58, a width 60, and a length 62. Such measurements 58, 60, 62 of the second airflow feature 56B are, for the embodiment shown, equal to the corresponding measurements 58, 60, 62 of the first airflow feature 56A. However, in other embodiments, the measurements 58, 60, 62 of the second airflow feature 56B may have any other suitable value within one or more the ranges set forth above. Further, it will be appreciated that in certain exemplary embodiments, not all of the cooling holes 44 may include the same configuration of airflow features 56 positioned adjacent thereto, or may not include any airflow features 56 positioned adjacent thereto. For example, in certain embodiments, some cooling holes 44 may include airflow features 56 having different heights, widths, lengths, orientations, etc. positioned adjacent thereto. Further, in certain exemplary embodiments, each of the airflow features 56 positioned adjacent to a given cooling hole 44 may have the same configuration (e.g., size and shape), or alternatively may have different configurations (e.g., size and shape).

Further, it will be appreciated that for the embodiment depicted in FIGS. 3 and 4, the first film cooling hole 44A is one of a plurality of film cooling holes 44, and that each of the plurality of film cooling holes 44 includes a first airflow feature 56A and a second airflow feature 56B configured in substantially the same manner as the first and second airflow features 56A, 56B positioned adjacent to the outlet 52A of the first film cooling hole 44A, described above. For example, the measurements of the first and second airflow features 56A, 56B positioned adjacent to the outlets 52 of the other cooling holes 44 depicted may be substantially the same as the measurements 58, 60, 62 of the first and second airflow features 56A, 56B positioned adjacent to the outlet 52A of the first film cooling hole 44A.

Further, it should be appreciated that for the embodiment depicted, the liner 50 includes the airflow features 56 formed integrally with a base wall portion 61 of the liner 50. For example, the liner 50 may be formed as a single component using, e.g., 3D printing/additive manufacturing processes to form the liner 50. Accordingly, in certain embodiments, the airflow features 56 and base wall portion 61 may be formed integrally as a single, continuous component. However, in other exemplary embodiments, the liner 50 may be formed in any other suitable manner.

As will also be appreciated from the view depicted in FIG. 4, for the embodiment depicted, the airflow features 56 each define an aerodynamic profile. As used herein, the term “aerodynamic profile” refers generally to including no sharp or jagged edges exposed to an airflow thereover (e.g., only rounded edges having a radius approximately equal to or greater than the smallest dimension the airflow feature 56, such as the smallest of its height, width, or length). Further, as is seen in FIG. 4, each of the airflow features 56 defines a perimeter shape. For the embodiment depicted, the perimeter shape of each airflow feature 56 is substantially an ellipse, a circle, or an oval, and more specifically still, for the embodiment depicted, is substantially a circle.

Notably, however, in other exemplary embodiments, one or more of the airflow features 56 may define one or more sharp edges, and may have any other suitable perimeter shape. For example, inclusion of sharp edges may be desirable to generate turbulence and increase airflow mixing.

Additionally, it will be appreciated that in other exemplary embodiments, the airflow feature(s) 56 may have any other suitable configuration for modifying an airflow provided through an outlet 52 of a film cooling hole 44. For example, referring now to FIG. 5, providing a cross-sectional view of a liner 50 in accordance with another exemplary embodiment of the present disclosure, it will be appreciated that in other example embodiments, one or both of the first airflow feature 56A and second airflow feature 56B may instead be configured as an indentation on the first side 36 of the liner 50. Specifically, for the embodiment of FIG. 5, both of the first airflow feature 56A and the second airflow feature 56B are configured as indentations in the first side 36 of the liner 50. It will be appreciated that the first and second airflow features 56A, 56B of FIG. 5 may define a height 58, a width 60, and a length 62 (similar to the features 56A, 56B described above with reference to FIG. 4). The length 62 and the width 60 may be defined in the same manner as the length 62 and the width 60 of the first and second airflow features 56A, 56B described above with reference to FIG. 4. Further, the heights 58 of the first and second airflow features 56A, 56B of FIG. 5, configured as indentations, are similarly defined in a direction perpendicular to the airflow direction A and transverse direction T, relative to a surrounding surface 54 of the first side 36 of the liner 50.

It will be appreciated, however, that in still other exemplary embodiments of the present disclosure, one of the first airflow feature 56A and second airflow feature 56B may be configured as a protrusion, and the other of the first airflow feature 56A and the second airflow feature 56B may be configured as an indentation. Moreover, it will be appreciated that in still other exemplary embodiments, the liner 50 may not include both of the first airflow feature 56A and the second airflow feature 56B positioned adjacent to the outlets 52 of the film cooling holes 44. For example, referring now to FIGS. 6 and 7, each providing a plan view of a first side 36 of a liner 50 in accordance with other exemplary embodiments of the present disclosure, it will be appreciated that in certain exemplary embodiments, the liner 50 may only include a single airflow feature 56 positioned adjacent to an outlet 52 of each of the respective film cooling holes 44 in the location of the first airflow feature 56A in FIG. 3 (see FIG. 7) or in the location of the second airflow feature 56B in FIG. 3 (see FIG. 6). Accordingly, in each of these embodiments, it will be appreciated that each airflow feature 56 included is offset from the outlet 52 of the respective film cooling hole 44 along the transverse direction T. However, in other embodiments, each airflow feature 56 may instead be substantially aligned with the outlet 52 of the respective film cooling hole 44 along the transverse direction T.

A liner 50 including airflow features 56 configured in accordance with one or more of these embodiments may assist with the cooling of the liner 50, as will be discussed in greater detail below.

Moreover, referring now to FIG. 8, providing a plan view of a first side 36 of a liner 50 in accordance with yet another example embodiment of the present disclosure, it will be appreciated that in still other exemplary embodiments, the airflow feature(s) 56 may be positioned at any other suitable location adjacent to the outlet 52A of the first film cooling hole 44A (and further adjacent to the outlets 52 of each of the plurality of film cooling holes 44). Specifically, for the embodiment of FIG. 8, it will be appreciated that the liner 50 includes an airflow feature 56 on the first side 36 of the liner 50 adjacent to the outlet 52 of the film cooling hole 44, and more specifically, adjacent to the outlet 52A of the first film cooling hole 44A, positioned at least partially downstream of the outlet 52A of the first film cooling hole 44A along the airflow direction A. More specifically, for the embodiment of FIG. 8, the airflow feature 56 is a first airflow feature 56A and the liner 50 further includes a second airflow feature 56B also positioned at least partially downstream of the outlet 52A along the airflow direction A, with the second airflow feature 56B spaced from the first airflow feature 56A along the transverse direction T. In at least certain exemplary embodiments, the first airflow feature 56A and the second airflow feature 56B on the liner 50 may be protrusions on the first side 36 of the liner 50 extending into the combustion chamber 20 (similar to the embodiment depicted in FIG. 4). However, in other embodiments, the first airflow feature 56A and the second airflow feature 56B on the liner 50 may each be indentations on the first side 36 of the liner 50 (similar to the embodiment depicted in FIG. 5). Alternatively, still, in other embodiments, one of the first airflow feature 56A and the second airflow feature 56B may be configured as a protrusion extending into the combustion chamber 20 and the other of the first airflow feature 56A and the second airflow feature 56B may be configured as an indentation on the first side 36 of the liner 50.

Further, as with the embodiments described above, it will be appreciated that in still other exemplary embodiments the liner 50 may not include both the first airflow feature 56A and the second airflow feature 56B adjacent to the first outlet 52A of the first film cooling hole 44A. For example, referring now also to FIGS. 9 and 10, each providing a plan view of a first side 36 of the liner 50 in accordance with additional exemplary embodiments of the present disclosure, it will be appreciated that in certain exemplary embodiments, the liner 50 may only include a single airflow feature 56 positioned adjacent to the outlet 52A of the first film cooling hole 44A in the location of the first airflow feature 56A in FIG. 8 (see FIG. 10) or in the location of the second airflow feature 56B in FIG. 8 (see FIG. 9). Accordingly, in each of these embodiments, it will be appreciated that the airflow feature 56 included is offset from the outlet 52A of the first film cooling hole 44A along the transverse direction T and located at least partially downstream of the outlet 52A of the first film cooling hole 44A. However, in other embodiments, the airflow feature 56 may instead be substantially aligned with the outlet 52A of the first film cooling hole 44A along the transverse direction T.

Notably, in each of the embodiments described above with reference to FIGS. 8 through 10, the liners 50 include airflow feature(s) 56 positioned adjacent to the outlets 52 of each of the plurality of film cooling holes 44, with each of these airflow feature(s) 56 configured in substantially the same manner as the airflow feature(s) 56 described above as being positioned adjacent to the outlet 52A of the first film cooling hole 44A.

A liner 50 including airflow features 56 configured in accordance with one or more of these embodiments may assist with the cooling of the liner 50, as will be discussed in greater detail below.

Referring now to FIG. 11, a plan view of a first side 36 of a liner 50 in accordance with yet another exemplary embodiment of the present disclosure is provided. The embodiment of FIG. 11 may be configured in a similar manner to one or more the exemplary liners 50 described above with reference to, e.g., FIGS. 2 through 10. For example, the exemplary liner 50 of FIG. 11 defines a film cooling hole 44, and more specifically, a first film cooling hole 44A having an outlet 52A on a first side 36 thereof. In addition, the liner 50 includes a first airflow feature 56A and a second airflow feature 56B, with the first and second airflow features 56A, 56B positioned adjacent to the outlet 52A of the first film cooling hole 44A and position at least partially upstream of the outlet 52A along an airflow direction A. Additionally, the first and second airflow features 56A, 56B are spaced from one another along the transverse direction T.

Moreover, for the embodiment of FIG. 11, the liner 50 further includes a third airflow feature 56C and a fourth airflow feature 56D. The third airflow feature 56C and the fourth airflow feature 56D are each positioned at least partially downstream of the outlet 52A of the first film cooling hole 44A along the airflow direction A and are similarly spaced from one another along the transverse direction T. Accordingly, for the embodiment depicted, the liner 50 includes two airflow features 56 position at least partially upstream of the outlet 52A of the first film cooling hole 44A and at least two airflow features 56 positioned at least partially downstream of the outlet 52A of the first film cooling hole 44A.

It will be appreciated that in at least certain embodiments, at least one of the first airflow feature 56A, the second airflow feature 56B, the third airflow feature 56C, and the fourth airflow feature 56D is a protrusion extending into the combustion chamber 20, such as the exemplary airflow features 56 depicted in FIG. 4. For example, in certain exemplary embodiments, each of the first airflow feature 56A, second airflow feature 56B, third airflow feature 56C, and fourth airflow feature 56D may be configured as protrusions extending into the combustion chamber 20. Additionally, or alternatively however, in other exemplary embodiments at least one of the first airflow feature 56A, the second airflow feature 56B, the third airflow feature 56C, and the fourth airflow feature 56D may be an indentation on the first side 36 of the liner 50, such as the exemplary airflow features 56 depicted in FIG. 5. For example, in certain exemplary embodiments, each of the first airflow feature 56A, second airflow feature 56B, third airflow feature 56C, and fourth airflow feature 56D may be configured as indentations on the first side 36 of the liner 50.

Moreover, referring now to FIG. 12, providing a plan view of a first side 36 of a liner 50 in accordance with yet another example embodiment of the present disclosure, it will be appreciated that in still other exemplary embodiments, the airflow feature(s) 56 may be positioned at any other suitable location adjacent to the outlet 52A of the first film cooling hole 44A. Specifically, for the embodiment of FIG. 12, it will be appreciated that the liner 50 includes an airflow feature 56 on the first side 36 of the liner 50 adjacent to the outlet 52 of the film cooling hole 44, and more specifically, adjacent to the outlet 52A of the first film cooling hole 44A, substantially aligned with the outlet 52A of the first film cooling hole 44A along the transverse direction T. More specifically, for the embodiment of FIG. 12, the airflow feature 56 is a first airflow feature 56A and the liner 50 further includes a second airflow feature 56B also substantially aligned with the outlet 52A along the transverse direction T, with the second airflow feature 56B positioned on an opposite side of the outlet 52A from the first airflow feature 56A along the transverse direction T. It will be appreciated, that as used herein, the term “substantially aligned with,” along the transverse direction T, refers to a center point along the airflow direction A of the airflow feature 56 (i.e., half of the length 62) being aligned with a center point of the outlet 52 of the film cooling hole 44 to which it is positioned adjacent to along the transverse direction T, or spaced no more than 0.5 times the diameter 64 of the outlet 52 from alignment with the center point of the outlet 52 along the transverse direction T.

In at least certain exemplary embodiments, the first airflow feature 56A and the second airflow feature 56B on the liner 50 may be protrusions on the first side 36 of the liner 50 extending into the combustion chamber 20 (similar to the embodiment depicted in FIG. 4). However, in other embodiments, the first airflow feature 56A and the second airflow feature 56B on the liner 50 may each be indentations on the first side 36 of the liner 50 (similar to the embodiment depicted in FIG. 5). Alternatively, still, in other embodiments, one of the first airflow feature 56A and the second airflow feature 56B may be configured as a protrusion extending into the combustion chamber 20 and the other of the first airflow feature 56A and the second airflow feature 56B may be configured as an indentation on the first side 36 of the liner 50.

Further, as with the embodiments described above, it will be appreciated that in still other exemplary embodiments the liner 50 may not include both the first airflow feature 56A and the second airflow feature 56B. For example, referring now also to FIGS. 13 and 14, each providing a plan view of a first side 36 of a liner 50 in accordance with additional exemplary embodiments of the present disclosure, it will be appreciated that in certain exemplary embodiments, the liner 50 may only include a single airflow feature 56 positioned adjacent to an outlet 52A of a first film cooling hole 44A in the location of the first airflow feature 56A in FIG. 12 (see FIG. 14) or in the location of the second airflow feature 56B in FIG. 12 (see FIG. 13). Accordingly, in each of these embodiments, it will be appreciated that the airflow feature 56 included is substantially aligned with the outlet 52A of the first film cooling hole 44A along the transverse direction T. Such may assist with the cooling of the liner 50, as we discussed in greater detail below.

Notably, in each of the embodiments described above with reference to FIGS. 11 through 14, the liners 50 include airflow feature(s) 56 positioned adjacent to the outlets 52 of each of the plurality of film cooling holes 44, with each of these airflow feature(s) 56 configured in substantially the same manner as the airflow feature(s) 56 described above as being positioned adjacent to the outlet 52A of the first film cooling hole 44A.

Further, it will be appreciated that in still other embodiments of the present disclosure, the airflow feature(s) 56 may have any other suitable shape. For example, referring now to FIGS. 15 and 16, plan views are provided of first sides 36 of liners 50 in accordance with still other exemplary embodiments the present disclosure, each including one or more airflow features 56. Referring particularly to FIG. 15, the liner 50 depicted defines a film cooling hole 44, more specifically, a first film cooling hole 44A, having an outlet 52A on the first side 36 thereof. Additionally, the liner 50 includes an airflow feature 56 positioned adjacent to the outlet 52A of the first film cooling hole 44A on the first side 36 of the liner 50. For the embodiment shown, the airflow feature 56 defines a length 62 along an airflow direction A and a width 60 along a transverse direction T. However, unlike the embodiments described above, for the embodiment shown, the width 60 of the airflow feature 56 is greater than the length 62 of the airflow feature 56 and up to about five (5) times the length 62 of the airflow feature 56. For example, for the embodiment shown, the width 60 of the airflow feature 56 may be at least about 1.25 times the length 62 of the airflow feature 56 and up to about three (3) times the length 62 of the airflow feature 56. In such a manner, it will also be appreciated that for the embodiment shown, the width 60 of the airflow feature 56 is also greater than a diameter 64 of the film cooling hole 44 defined through the liner 50.

Notably, for the embodiment of FIG. 15, the airflow feature 56 is positioned at least partially upstream of the outlet 52A of the first film cooling hole 44A along the airflow direction A, and more specifically, positioned completely upstream of the outlet 52A of the first film cooling hole 44A along the airflow direction A. However, in other embodiments, the airflow feature 56 may instead be positioned at any other suitable location. For example, referring particularly to FIG. 16, for the embodiment depicted, the airflow feature 56 is instead positioned at least partially downstream of the outlet 52A of the first film cooling hole 44A along the airflow direction A, and more particularly, positioned completely downstream of the outlet 52A of the first film cooling hole 44A along the airflow direction A.

Furthermore, it will be appreciated that the exemplary embodiments provided in FIGS. 15 and 16 are provided by way of example only, and that in other exemplary embodiments, the liner 50 may include any suitable combination of airflow features 56 positioned adjacent to an outlet 52 of a film cooling hole 44 defined by a liner 50. For example, referring also to FIG. 17, providing a plan view of a first side 36 of the liner 50 in accordance with yet another exemplary embodiment of the present disclosure, it will be appreciated that in at least certain exemplary embodiments, an airflow feature 56 defining a relatively high aspect ratio (i.e., a relatively high ratio of width 60 to length 62; see FIGS. 15 and 16) may be used in conjunction with substantially circular airflow features 56, with each of these airflow features 56 position at least partially upstream of a first outlet 52A of a film cooling hole 44A.

Notably, in each of the embodiments described above with reference to FIGS. 15 and 16, the liners 50 include airflow feature(s) 56 positioned adjacent to the outlets 52 of each of the plurality of film cooling holes 44, with each of these airflow feature(s) 56 configured in substantially the same manner as the airflow feature(s) 56 described above as being positioned adjacent to the outlet 52A of the first film cooling hole 44A.

In still other exemplary embodiments the present disclosure, however, the liner 50 may have still other suitable configurations. For example, referring now to FIGS. 18 and 19, a liner 50 in accordance with another exemplary embodiment of the present disclosure is provided. FIG. 18 provides a plan view of a first side 36 of a liner 50 in accordance with yet another example embodiment of the present disclosure, and FIG. 19 provides a cross-sectional view of the exemplary liner 50 of FIG. 18, along Line 19-19 in FIG. 18.

For the embodiment of FIGS. 18 and 19, the liner 50 generally defines a film cooling hole 44 and an airflow feature 56 on the first side 36 of the liner 50 adjacent to an outlet 52 of the film cooling hole 44. The airflow feature 56 is substantially aligned with the outlet 52 of the film cooling hole 44 along the airflow direction A. Moreover, for the embodiment of FIGS. 18 and 19, the airflow feature 56 is a first airflow feature 56A and the liner 50 further includes a second airflow feature 56B, a third airflow feature 56C, and a fourth airflow feature 56D, each substantially aligned with the outlet 5A along the airflow direction A. It will be appreciated, that as used herein, the term “substantially aligned with,” along the airflow direction A, refers to a center point along the transverse direction T of the airflow feature 56 (i.e., half of the width 60) being aligned with a center point of the outlet 52 of the film cooling hole 44 to which it is positioned adjacent to along the along airflow direction A, or spaced no more than 0.5 times the diameter 64 of the outlet 52 from alignment with the center point of the outlet 52 along the airflow direction A.

For the embodiment depicted, the first airflow feature 56A and the fourth airflow feature 56D of the liner 50 are configured as protrusions on the first side 36 of the liner 50 extending into the combustion chamber 20 (similar to the embodiment depicted in FIG. 4), while the second airflow feature 56B and the third airflow feature 56C of the liner 50 are each configured as indentations on the first side 36 of the liner 50 (similar to the embodiment depicted in FIG. 5). Further, for the embodiment shown, the first and second airflow features 56A, 56B are each aligned with one another along the airflow direction A, and positioned adjacent to one another along the airflow direction A (i.e., for the embodiment shown, spaced along the airflow direction A in such a manner that a downstream end of the first airflow feature 56A meets an upstream end of the second airflow feature 56B). Similarly, the third and fourth airflow features 56C, 56D are similarly aligned with one another along the airflow direction A and positioned adjacent to one another along the airflow direction A (i.e., for the embodiment shown, spaced along the airflow direction A in such a manner that a downstream end of the third airflow feature 56C meets an upstream end of the fourth airflow feature 56D). Notably, although for the embodiment of FIGS. 18 and 19 the adjacent airflow features (i.e., airflow features 56A and 56B, as well as airflow features 56D and 56D) are paired off as an indentation and a protrusion, in other embodiments, adjacent airflow features 56 may each be protrusions, or may each be indentations.

Further, it should be appreciated that other configurations are contemplated as well. For example, in other exemplary embodiments, any other suitable combination of the configurations shown in one or more of the embodiments of FIGS. 2 through 19 may be provided. For example, in other exemplary embodiments, the liner 50 may include one or more airflow features 56 positioned in a similar manner to one or more the above embodiments, having a size and/or shape of an airflow feature of one or more of the above embodiments, configured as a protrusion and/or indentation, etc.

Inclusion of a liner 50 having one or more of the exemplary airflow features 56 positioned adjacent to the outlets 52 of each of the plurality of film cooling holes 44 defined therein may assist with cooling the liner 50 during operation of the combustor and gas turbine engine within which the liner 50 is installed. For example, inclusion of one or more the above exemplary airflow features 56 may create a transverse pressure gradient (i.e., a pressure gradient along the transverse direction T of the hot side of the liner 50) that acts as a jet deflector of the cooling airflow through the film cooling holes 44. Such may therefore act to reduce a strength of a counter-rotating vortex pair that typically forms when cooling airflow is provided through film cooling holes 44 to a hot side of the liner 50. For example, inclusion of one or more the exemplary airflow features 56 described herein may create a vortex along one side of the counter-rotating vortex pair to reduce a strength of the gas impingement within the combustion chamber 20. Such may lead to a reduced impingement of hot combustion gases into the film (i.e., the relatively cool air film on the hot side of the liner) leading to improved film cooling effectiveness along the first side 36 of the liner 50.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A gas turbine engine combustor comprising: a liner defining at least in part a combustion chamber, a first side exposed to the combustion chamber, a second side opposite the first side, and a film cooling hole extending from the second side to the first side, the film cooling hole defining an outlet on the first side of the liner, the liner comprising an airflow feature on the first side of the of the liner adjacent to the outlet of the film cooling hole to increase a cooling of the liner.
 2. The gas turbine engine of claim 1, wherein the combustion chamber defines an airflow direction over the outlet of the film cooling hole on the first side of the liner, and wherein the airflow feature is positioned at least partially downstream of the outlet along the airflow direction.
 3. The gas turbine engine of claim 2, wherein the airflow feature is a first airflow feature, wherein the liner further comprises a second airflow feature also positioned at least partially downstream of the outlet along the airflow direction, wherein the combustion chamber further defines a transverse direction perpendicular to the airflow direction, and wherein the second airflow feature is spaced from the first airflow feature along the transverse direction.
 4. The gas turbine engine of claim 3, wherein the first airflow feature is a protrusion on the first side of the liner extending into the combustion chamber, and wherein the second airflow feature is an indentation on the first side of liner.
 5. The gas turbine engine of claim 1, wherein the combustion chamber defines an airflow direction over the outlet of the film cooling hole on the first side of the liner, and wherein the airflow feature is positioned at least partially upstream of the outlet along the airflow direction.
 6. The gas turbine engine of claim 5, wherein the airflow feature is a first airflow feature, wherein the liner further comprises a second airflow feature also positioned at least partially upstream of the outlet along the airflow direction, wherein the combustion chamber further defines a transverse direction perpendicular to the airflow direction, and wherein the second airflow feature is spaced from the first airflow feature along the transverse direction.
 7. The gas turbine engine of claim 6, wherein the first airflow feature is a protrusion on the first side of the liner extending into the combustion chamber, and wherein the second airflow feature is an indentation on the first side of liner.
 8. The gas turbine engine of claim 6, wherein the first airflow feature is a protrusion on the first side of the liner extending into the combustion chamber, and wherein the second airflow feature is also a protrusion on the first side of the liner extending into the combustion chamber.
 9. The gas turbine engine of claim 6, wherein the liner further comprises a third airflow feature and a fourth airflow feature, wherein the third airflow feature and the fourth airflow feature are each positioned at least partially downstream of the outlet along the airflow direction and spaced from one another along the transverse direction.
 10. The gas turbine engine of claim 9, wherein at least one of the first airflow feature, the second airflow feature, the third airflow feature, and the fourth airflow feature is a protrusion extending into the combustion chamber, and wherein at least one of the first airflow feature, the second airflow feature, the third airflow feature, and the fourth airflow feature is an indentation on the first side of liner.
 11. The gas turbine engine of claim 1, wherein the combustion chamber defines an airflow direction over the outlet of the film cooling hole on the first side of the liner, wherein the airflow feature is a first airflow feature, wherein the liner further comprises a second airflow feature, wherein the first and second airflow features are aligned with one another and the outlet of the film cooling hole along the airflow direction, and wherein the first airflow feature is positioned adjacent to the second airflow feature along the airflow direction.
 12. The gas turbine engine of claim 1, wherein the combustion chamber defines an airflow direction over the film cooling hole on the first side of the liner and a transverse direction perpendicular to the airflow direction, wherein the airflow feature defines a length along the airflow direction and a width along the transverse direction, and wherein the width of the airflow feature is greater than the length of the airflow feature and up to about five times the length of the airflow feature.
 13. The gas turbine engine of claim 1, wherein the film cooling hole defines a diameter at the outlet, wherein the airflow feature defines a width and a height, wherein the width of the airflow feature is greater than or equal to about 0.1 times the diameter of the of the film cooling hole and up to about 6 times the diameter of the film cooling hole, and wherein the height of the airflow feature is greater than or equal to about 0.1 times the diameter of the film cooling hole and up to about 6 times the diameter of the film cooling hole.
 14. The gas turbine engine of claim 1, wherein the film cooling hole is a first film cooling hole of a plurality of film cooling holes defined by the liner.
 15. The gas turbine engine of claim 1, wherein the film cooling hole defines a substantially constant diameter along a length thereof.
 16. A gas turbine engine comprising: a combustion section comprising a combustor liner, the combustor liner defining at least in part a combustion chamber, a hot side exposed to the combustion chamber, a cold side opposite the hot side, and a plurality of film cooling holes extending from the cold side to the hot side, the plurality of film cooling holes each defining an outlet on the hot side of the liner, the liner comprising a plurality of airflow features on the hot side of the of the liner, each airflow feature of the plurality of airflow features positioned adjacent to the outlet of one of the plurality of film cooling holes to increase a cooling of the liner.
 17. The gas turbine engine of claim 16, wherein the combustion chamber defines an airflow direction over the outlets of the plurality of film cooling holes on the hot side of the liner, and wherein the airflow features are each positioned at least partially downstream of the outlet of one of the plurality of film cooling holes along the airflow direction.
 18. The gas turbine engine of claim 16, wherein the combustion chamber defines an airflow direction over the outlets of the plurality of film cooling holes on the hot side of the liner, and wherein the airflow features are each positioned at least partially upstream of the outlet of one of the plurality of film cooling holes along the airflow direction.
 19. The gas turbine engine of claim 16, wherein the combustion chamber defines an airflow direction over the outlets of the plurality of film cooling holes on the hot side of the liner and a transverse direction perpendicular to the airflow direction, wherein each airflow feature defines a length along the airflow direction and a width along the transverse direction, and wherein the width of each airflow feature is greater than the length of the airflow feature and up to about five times the length of the airflow feature.
 20. The gas turbine engine of claim 16, wherein a first film cooling hole of the plurality of film cooling holes defines a diameter at its outlet, wherein a first airflow feature of the plurality of airflow features defines a width and a height, wherein the width of the first airflow feature is greater than or equal to about 0.1 times the diameter of the of the first film cooling hole and up to about 6 times the diameter of the first film cooling hole, and wherein the height of the first airflow feature is greater than or equal to about 0.1 times the diameter of the first film cooling hole and up to about 6 times the diameter of the first film cooling hole. 